All sexually transmitted diseases (STDs) can be transmitted through oral sex, including: chlamydia, gonorrhea, syphilis, HPV (genital warts), herpes, and HIV. Both performer and receiver are at risk for STD transmission; however, the performer is at much higher risk. Placing a barrier (i.e. male condom or dental dam) between the mouth and genitals can reduce the risk of disease transmission during oral sex.

Abstaining from intercourse is one way to reduce your risk of getting cervical cancer, but if you substitute oral sex as your sexual contact of choice, you raise the chances of developing oral cancer, instead.

“A recent study at Johns Hopkins Oncology Center studied 253 patients diagnosed with head and neck cancer [and found that in] 25 percent of the cases, the tissue taken from the tumors was HPV positive and HPV-16 was present in 90 percent of these positive tissues,” says Dr Smith. “The 25 percent were also non-smokers, further establishing the link between HPV and oral cancer (smoking has also been closely linked to oral cancer). Another study stated that people who had a previous oral infection of HPV were 32 times more likely to develop oral cancer
Oral cancer claims more lives than cervical cancer
I hope this helps